A geographic information system (GIS) is a system designed to capture, store, analyze, and present many types of data that are linked to a spatial location or area. In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology. Examples of data that are geographically oriented are population census blocks, county property tax maps, and postal zip codes.
A GIS is typically custom-designed for the needs of an organization, and the spatial boundaries of each data subset may be represented by squares, rectangles, polygons, curves, or other complex shapes. The shapes of spatial area boundaries may be jurisdictional, purpose, or application oriented. GIS uses spatial-temporal location as the key index variable for all information being collected into the GIS database. Location data may be recorded, for example, as dates/times of occurrence, along with a combination of longitude, latitude, and elevation. The coordinates ultimately refer to physical locations or items such as highway mile markers, surveyor benchmarks, or street intersections.
Generally, GIS applications are tools that allow users to create interactive searches, analyze spatial information, edit data in maps, and present the results of these operations. Examples of GIS software applications are Esri ArcGIS®, which is a commercial suite of GIS applications, and Natural Earth, which is an open source map data set. ArcGIS® is a registered trademark of Esri in the United States, the European Community, or certain other jurisdictions. The Open Geospatial Consortium (OGC), originating in 1994, developed standards for geospatial content and services, GIS data processing and data sharing. The OGC created a features and geometry specification, and sets standards for adding spatial functionality to database systems. A spatial database management system is optimized to store and query data that represents objects defined in a geometric space using a geometry or feature, such as a polygon representing a county border.